NEW YORK — President-elect Donald Trump acknowledged for the first time here Wednesday that Russia was responsible for hacking the Democratic Party during last year’s election, but he denied that the leaks were intended to boost him and argued that Moscow would cease cyberattacks on the United States once he is sworn in.

In a rollicking hour-long news conference, Trump furiously denounced as “fake news” the reports that Russia had obtained salacious intelligence that could compromise him. He suggested that any damaging information collected by Russian President Vladimir Putin’s administration would already have been released — and he celebrated what had leaked out about Democratic nominee Hillary Clinton.

“As far as hacking, I think it was Russia,” Mr. Trump said. “Hacking’s bad, and it shouldn’t be done. But look at the things that were hacked, look at what was learned from that hacking.”

Allowing his hostility and contempt toward the U.S. intelligence community to again burst into public view, Trump also reaffirmed his belief — first expressed in a tweet earlier Wednesday morning — that intelligence officials were behaving as though they were in “Nazi Germany” with what he termed “disgraceful” leaks to the media. The Anti-Defamation League asked Trump to apologize for trivializing the Holocaust.

Trump made a series of promises but provided little specific evidence on how he would deliver them. He vowed to repeal and replace President Obama’s Affordable Care Act quickly and nearly simultaneously (“could be the same hour”); to start building a wall along the U.S. border with Mexico before persuading the Mexican government to pay for it (“that will happen, whether it’s a tax or whether it’s a payment”); and unveiled how he is disentangling himself from the management of his business empire while still refusing to divest himself of his financial interests.

Russia loomed large over President-elect Donald Trump’s news conference and his pick for secretary of state Rex Tillerson’s confirmation hearing on Jan. 11. (Video: Bastien Inzaurralde/Photo: Jabin Botsford/The Washington Post)

Trump also said he planned to announce a nominee to fill the Supreme Court vacancy left by the death of Justice Antonin Scalia within two weeks of his Jan. 20 inauguration, having already reviewed a list of about 20 candidates recommended by conservatives at the Federalist Society and the Heritage Foundation. And he promised to bring jobs to the states that supported him in November, calling himself “the greatest jobs producer that God ever created.”

In a performance that was by turns considered, combative and carnivalesque, Trump also definitively confirmed that winning the presidency has not changed his public presentation to that of a more traditional statesman.

Instead, he repeatedly lashed out at the news media. He shushed correspondents from CNN — “You are fake news,” he said — which broke the news late Tuesday that Trump and President Obama had been briefed on allegations that Russian intelligence services have compromising material and information on Trump’s personal life and finances.

Trump also went after BuzzFeed, which published a document Tuesday outlining some of the unverified allegations, which were based on research done by an outside entity engaged in political consulting work and led by a former high-ranking British intelligence official. Trump called BuzzFeed a “failing pile of garbage” and warned it would “suffer the consequences” for publishing the dossier.

About 300 journalists packed into the marble lobby of Trump Tower for the president-elect’s first full-fledged news conference since July 27, when, among other pronouncements, Trump urged the Russian government to find and release tens of thousands of Clinton’s private emails.

Six months later, the subject of Russian hacking still clouds Trump’s transition to power, and questions about the hacking attacks dominated Wednesday’s news conference. At first, Trump refused to say whether he or anyone on his campaign had been in contact with Russia, but he clarified as he left the news conference, telling reporters near the elevators that neither he nor his team had any contact with Russia about his campaign.

Trump also insisted that the warm relationship…